The invention relates to a camera apparatus for an endoscope, and more particularly, to a camera apparatus detachably mounted on an endoscope and having its various functions associated with photographing operations to be electrically driven and controlled.
As is well known, cameras manufactured for use with an endoscope are adapted to be mounted on an endoscope to take a picture of the interior of a coeliac cavity. A camera of this kind is known in which a series of functions including a shutter release and a film winding associated with a photographing operation are electrically driven and controlled. A camera which is electrically driven and controlled in this manner contains a variety of electrical components and electrical circuits, which can be categorized in a manner described below, depending on the magnitude of their power dissipation and the timing when they require a power supply.
1. Electrical components having an increased power dissipation and which need be supplied with power only during a photographing operation:
(a) an electric motor which effects a film winding as well as a charging operation for operating a mirror shutter release;
(b) an electromagnet which controls the operation of the mirror shutter;
(c) light emitting assembly comprising a combination of segment-shaped elements such as photodiodes and which is utilized to enter various data such as picture number, date, time of day and the number of film frames onto a film; and
(d) detection and display means formed by light emitting diodes or the like for detecting and displaying the film speed and the voltage of an internally housed battery;
2. Electrical circuits which exhibit a reduced power dissipation and which need be supplied with power only during a photographing operation:
(a) a control circuit associated with the motor;
(b) a control circuit associated with the electromagnet;
(c) a control circuit associated with the light emitting assembly; and
(d) a control circuit associated with the detection and display means;
3. Electrical components and circuits which must be normally supplied with power:
(a) a sequence control circuit for controlling the sequence of operation of the motor control circuit, the electromagnet control circuit, the light emitting assembly control circuit, the detection and display means control circuit, and a display control circuit to be described later;
(b) a display formed by a combination of segment-shaped elements such as liquid crystal elements for providing a display, externally of the camera apparatus, of various data including picture number, date, time of day and the number of film frames; and
(c) a control circuit associated with the display and including a clock circuit which must be maintained in operation to provide a display of the date and the time of day and a storage circuit for storing the number of film frames.
In order to reduce the power dissipation of a battery which is internally housed within the camera, and thereby increase the useful life of the battery prior art cameras of the type described above supply power to the components and circuits mentioned under the item 3 which normally require energization, from the internal battery while supplying other components and circuits from an external power source such as the source provided within a light source device of an endoscope used only during a photographing operation. Alternatively, those components and circuits which do not require energization at all times are supplied from the internal battery only during a photographing operation.
The components and circuits mentioned under items 1 and 2 which require a power supply only during a photographing operation may be fed by connection with an external source at the desired times. By way of example, an energization of the electrical circuits of the camera apparatus may be started in response to the depression of a shutter release button (see U.S. Pat. No. 4,145,130) or in response to a movement of a film winding lever from its inoperative to its operative position. However, with these known approaches, the energization cannot be started unless a photographing operation is initiated. Consequently, it is impossible to provide an idle, automatic film winding by means of an internally housed motor or to provide a film winding in order to prevent fogging. Even if possible, the resulting operation will be a very troublesome one.